Self-test for unit 1.1 - 1.4: Attempt review 1 von 11 https://renewables-online.de/mod/quiz/review.php?attempt=486848&c... Dashboard / My courses / Green Hydrogen production by electrolysis - project development and financial evaluation / 1 / Self-test for unit 1.1 - 1.4 Started on State Completed on Time taken Wednesday, 11 October 2023, 9:39 PM Finished Wednesday, 11 October 2023, 10:02 PM 22 mins 55 secs Marks 11.08/13.00 Grade 85.26 out of 100.00 Feedback You passed with an excellent grade (80%-94.99%) 26.01.2024, 20:13 Self-test for unit 1.1 - 1.4: Attempt review 2 von 11 Question https://renewables-online.de/mod/quiz/review.php?attempt=486848&c... 1 Correct Mark 1.00 out of 1.00 The basic electrolyser A basic electrolyser generates oxygen and hydrogen gases. Drag and drop the correct elements to the appropriate location. O2 H2 Anode Your answer is correct. It may help to remember oxygen at the anode (both terms start with vowels); hydrogen at the cathode (both start with consonants). 26.01.2024, 20:13 Self-test for unit 1.1 - 1.4: Attempt review 3 von 11 Question https://renewables-online.de/mod/quiz/review.php?attempt=486848&c... 2 Correct Mark 1.00 out of 1.00 The water electrolysis reaction The reaction at the cathode is a hydrogen reduction gas and negatively charged The reaction at the anode is an oxidation reaction in which electrons are donated to the water to generate hydroxyl (OH-) ions: reaction that removes electrons and generates oxygen gas and positively charged hydrogen ions (H+): Your answer is correct. The correct answer is: The water electrolysis reaction The reaction at the cathode is a [reduction] reaction in which electrons are donated to the water to generate [hydrogen] gas and negatively charged [hydroxyl] (OH-) ions: The reaction at the anode is an [oxidation] reaction that removes [electrons] and generates oxygen gas and positively charged hydrogen ions (H+): Question 3 Correct Mark 1.00 out of 1.00 Uses of oxygen True or false: Oxygen can be used in various industrial processes, and as chemical feedstock in the manufacture of ammonia and methanol. Select one: True False Hydrogen, not oxygen, is used in the processes indicated. The correct answer is 'False'. 26.01.2024, 20:13 Self-test for unit 1.1 - 1.4: Attempt review 4 von 11 Question https://renewables-online.de/mod/quiz/review.php?attempt=486848&c... 4 Correct Mark 1.00 out of 1.00 The key components of an electrolyser plant Match the major component with its function or relevant characteristic. Transformers and rectifiers convert grid power into DC power Power supply Removes impurities from water Water supply and treatment Pipes, compressors, cooling, storage tanks Balance of plant Removes oxygen and water from hydrogen stream Hydrogen processing Where the electrolytic splitting of water into hydrogen and oxygen takes place Electrolyser stack Your answer is correct. The correct answer is: Transformers and rectifiers convert grid power into DC power → Power supply, Removes impurities from water → Water supply and treatment, Pipes, compressors, cooling, storage tanks → Balance of plant, Removes oxygen and water from hydrogen stream → Hydrogen processing, Where the electrolytic splitting of water into hydrogen and oxygen takes place → Electrolyser stack 26.01.2024, 20:13 Self-test for unit 1.1 - 1.4: Attempt review 5 von 11 Question https://renewables-online.de/mod/quiz/review.php?attempt=486848&c... 5 Correct Mark 1.00 out of 1.00 The basic electrolyser An electrolyser system is made up of several components and sub-systems. Drag and drop the names of the correct elements in an electrolyser system to the appropriate location. Electrolyser stack Feed supply water Your answer is correct. Transformer 26.01.2024, 20:13 Self-test for unit 1.1 - 1.4: Attempt review 6 von 11 Question https://renewables-online.de/mod/quiz/review.php?attempt=486848&c... 6 Partially correct Mark 0.75 out of 1.00 The water electrolysis reaction An electrolyser plant requires a high level of automation to ensure the technical specifications and system optimisation performance safe criteria. Electrolyser stacks are and efficient operation in accordance with modular in design, which enables to achieve the desired quantities of hydrogen. Your answer is partially correct. You have correctly selected 3. The correct answer is: The water electrolysis reaction An electrolyser plant requires a high level of automation to ensure the [safe] and efficient operation in accordance with technical specifications and [performance] criteria. Electrolyser stacks are [modular] in design, which enables system [scaling] to achieve the desired quantities of hydrogen. Question 7 Incorrect Mark 0.00 out of 1.00 Capacity of an electrolyser Which of the following is NOT a unit of measure used to express the production capacity of an electrolyser? kWh/kg kg/h Nm3/day kW kWh/day This is not correct. This is a less common but still meaningful unit of measure to express the capacity of an electrolyser. Your answer is incorrect. The correct answer is: kWh/kg 26.01.2024, 20:13 Self-test for unit 1.1 - 1.4: Attempt review 7 von 11 Question https://renewables-online.de/mod/quiz/review.php?attempt=486848&c... 8 Correct Mark 1.00 out of 1.00 Calculating specific production To calculate the amount of hydrogen that an electrolyser can produce, we use the following equation: Place the correct units into the gaps in the equation. kg/h kW/h kg/kW kg Your answer is correct. Question 9 Correct Mark 1.00 out of 1.00 Calculating specific production II An electrolyser with an installed capacity of 5000 kW and specific electricity consumption of 50 kWh/kg H2 should produce approximately how many kg of hydrogen (H2specificProduction) in a 24-hour period? 1200 480 24000 2400 Correct. 4800 Your answer is correct. The correct answer is: 2400 26.01.2024, 20:13 Self-test for unit 1.1 - 1.4: Attempt review 8 von 11 Question https://renewables-online.de/mod/quiz/review.php?attempt=486848&c... 10 Correct Mark 1.00 out of 1.00 System boundaries To compare the efficiency of two or more electrolyser systems, the relevant reference points must be specified under standard conditions and with equivalent system boundaries. Water treatment, automation, cooling, and compression typically add 10-20% to the electrolyser stack energy consumption. This additional demand will vary depending on factors including system capacity, water source and quality and ambient conditions . Your answer is correct. The correct answer is: System boundaries To compare the efficiency of two or more electrolyser systems, the relevant reference points must be specified under [standard] conditions and with equivalent system boundaries. Water treatment, automation, cooling, and compression typically add [10‑20%] to the electrolyser stack energy consumption. This additional demand will vary depending on factors including system capacity, water source and quality and [ambient conditions]. Question 11 Partially correct Mark 0.33 out of 1.00 Water consumption Match the water consumption amount with the appropriate electrolysis concept or system per kg H2. Typical evaporative cooling demand per kg H2 40-60 kg Stoichiometric input per kg H2 18-24 kg Average water consumption per kg H2 9 kg Your answer is partially correct. You have correctly selected 1. The correct answer is: Typical evaporative cooling demand per kg H2 → 40-60 kg, Stoichiometric input per kg H2 → 9 kg, Average water consumption per kg H2 → 18-24 kg 26.01.2024, 20:13 Self-test for unit 1.1 - 1.4: Attempt review 9 von 11 Question https://renewables-online.de/mod/quiz/review.php?attempt=486848&c... 12 Correct Mark 1.00 out of 1.00 Visualising system boundaries The efficiency of two or more electrolyser systems is only directly comparable using equivalent system boundaries. Identify the elements that belong in different boundaries in the schematic by dragging the system or item to its appropriate place Stack Power supply Water supply and purification Your answer is correct. 26.01.2024, 20:13 Self-test for unit 1.1 - 1.4: Attempt review 10 von 11 https://renewables-online.de/mod/quiz/review.php?attempt=486848&c... 26.01.2024, 20:13 Self-test for unit 1.1 - 1.4: Attempt review 11 von 11 Question https://renewables-online.de/mod/quiz/review.php?attempt=486848&c... 13 Correct Mark 1.00 out of 1.00 Water consumption What is the main reason that average water consumption in an electrolyser is not equal to the stoichiometric ratio? Electrolyser inefficiency Evaporation Water purification Correct. Water losses from leakage Your answer is correct. The main reason that average water consumption in an electrolyser is not equal to the stoichiometric ratio is water purification, which generates wastewater to remove the impurities. Estimates of water consumption vary a great deal; a likely average is around 18-24 kg water per kg H2. The correct answer is: Water purification ◄ Unit 1 – Sizing fundamentals of key onshore electrolyser plant components Self-test for unit 1.5 - 1.8 ► 26.01.2024, 20:13
